The 'Scream & Shout' singer generously went to a cash machine to withdraw five $20 bills for the street sleeper, but she started ''screaming'' as he went in for a hug and security staff leapt to her rescue because they thought she was being mugged.

''He said to her: 'Please help me, I'm at the end of my rope.' So she walked to a nearby cash machine and withdrew five $20 bills and gave them to him.

''He was so taken aback and happy he jumped up and lunged at her for a big bear hug. Britney started screaming and within seconds the shop's security guards had run over.''

But the 31-year-old pop megastar quickly explained she was just donating money to the homeless man and the situation was resolved.

A source told the Daily Star newspaper: ''The security men snatched the notes out of the man's hand and automatically thought he'd mugged her.

''Britney was frantically trying to explain, saying, 'No! No, give this man his money back, I gave it to him.'

''The man was so grateful and didn't actually seem that fussed by all the drama.''

Britney isn't the only generous celebrity around. Russell Brand gave his friends $2,400 to hand out to homeless people in Los Angeles over Christmas, and One Direction star Harry Styles splashed out $4,800 on pizza for some people living rough last year when he had a day off in Los Angeles.